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Influence of natural regeneration on fractal features of residue microaggregates in bauxite residue disposal areas

Zhu, F., Cheng, Q., Xue, S., Li, C., Hartley, W., Wu, C. and Tian, T. (2017) Influence of natural regeneration on fractal features of residue microaggregates in bauxite residue disposal areas. Land Degradation & Development.

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Official URL: https://doi.org/10.1002/ldr.2848

Abstract

Bauxite residue is often physically degraded, which limits vegetation establishment on the disposal areas. Microaggregate stability is an important physical property due to its significant effect on erosion and surface runoff, however this is rarely reported for bauxite residue. Native plant encroachment on a bauxite residue disposal area in Central China has revealed that natural regeneration may ameliorate the residue and help to support plant growth. Residue samples from five different disposal ages were collected to determine microaggregate stability and identify their fractal features. Following natural regeneration, the aggregate fraction 250-50 μm increased significantly from 27.4% to 40.3%, whilst the silt+clay size aggregate fraction decreased from 58.4% to 30.7%. With increasing disposal age, the residue clay dispersion ratio (CDR) ranged from 7.7% to 22.5%, whilst aggregated silt and clay (ASC) ranged from 15.3% to 19.0% indicating a stable microaggregate structure. The single-fractal dimension (D) of the residues for different disposal ages varied from 2.2 to 2.4. The high pH and salinity of bauxite residue indicated a high value of single-fractal dimension. The multi-fractal parameters of residue microaggregates, including capacity dimension (D0), information dimension (D1) and information dimension/capacity dimension (D1/D0) decreased which resulted in homogeneity following natural regeneration. Correlation analysis revealed that both single- and multi-fractal dimensions had significant correlations with residue microaggregate stability. Our results suggested that natural regeneration may improve microaggregate stability of bauxite residue, and fractal parameters of residue microaggregates may be used to describe residue microaggregate stability and the physical condition of bauxite residue.

Item Type: Article
Keywords: Bauxite residue disposal area, bauxite residue, natural regeneration, microaggregate stability, fractal features
Divisions: Crop and Environment Sciences
Depositing User: Ms Kath Osborn
Date Deposited: 23 Nov 2017 18:59
Last Modified: 18 Nov 2018 05:10
URI: http://hau.collections.crest.ac.uk/id/eprint/17215

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